土壤干湿处理与储存时间对土壤溶液组分离子活度及离子活度积的影响

采用真空置换法（ｖａｃｕｍｎｄｉｓｐｌａｃｅｍｅｎｔ）提取土壤溶液，研究了土壤温度及储存时间两种处理对离子化学形态电脑模型计算结果的影响．研究不同处理效应的电脑输出数据以负对数表示，计有：（１）Ｈ＋、Ｃａ２＋、Ａｌ３＋及ＳＯ的离子活度，（２）（Ａｌ＋）（ＯＨ）３、（Ａｌ３）２（ＯＨ）６（Ｈ４ＳｉＯ４）２及Ａｌ３＋）３．７７（Ｈ４ＳｉＯ４）３．２４（Ｋ＋）０．２４（Ｃａ）０．０８（Ｆｅ＋）０．２４（Ｍｇ）０．２０（ＯＨ）１２．８３的离子活度积和（３）Ｃａ２＋／Ａ１３＋的离子活度比．结果表明，储存期长短的影响比不同干湿处理为显著，两处理的交互影响很少见．根据ＰＨ—１／３ｐＡｌ对ＰＨ４ＳｉＯ４的图发现，无定形ＳｉＯ２、高岭土、绿泥化蛭石（ｈｙｄｒｏｘｙｉｎｔｅｒｉａｙｅｒｅｄｖｅｒｍｉｃｕｌｉｔｅ）及潜晶水铝矿（ｃｒｙｐｔｏｃｒｙｓｔａｌｌｉｎｅｇｉｂｂｓｉｔｅ）的稳定性几乎不受样品处理的影响，但是ＰＨ４ＳｉＯ４在土样风干后再湿润组中增加显著．当采用电脑模型分析土壤溶液组分中离子的化学形态时，土壤预处理的方法需要作较为详细的说明．

DRYING AND TIME OF INCUBATION EFFECTS ON IONIC ACTIVITIES AND ION ACTIVITY PRODUCTS OF SOIL SOLUTION COMPONENTS

The effect of soil moisture treatment and time of incubation on the results of ion speciation modeling was determined for soil solution displaced from Ultisol Ap and B horizons. The following output data (expressed as negative logarithms) were selected for consideration of sample treatment effect: ionic activities of H , Cab 2 A13 , and SO:, the IAP(Al3 )(OH)3, (Al3 )2(OW )6(H4SiO4)2, and (Al3 )3.37(H4SiO4)3.24(K) 0.24(Ca2 )0.08(Fe 3 )0.24(M g2 )0.20(OH-) 12.83, and the ion activity ratio Ca2 /Al3 . Time of incubation effects were more consequential than soil moisture treatment, and time by moisture treatment interactions were infrequent. Interpretations of stability relations for the mineral suite amorphous SiO2,kaolinite, hydroxinterlayered vermiculite, and cryptocrystalline gibbsite for data plotted as a function of PH-1 / 3 PAl vs pH4SiO4 were little affected by sample handling, but increase in pH4SiO4 with air drying and rewetting were apparent. Method of soil sample handling should be detailed when soil solution compositional analysis is modeled by ion speciation models with the assumption of stationary state conditions.